Question 1 (a)

  • Write the state of each substance for dissolving equation

    MgF2(s) Mg2+(aq) + 2 F-(aq)

    ![The Solubility Expression AaBb(s) aAb+ (aq) + bBa- (aq) Ksp = [Ab+]a [Ba-]b Example:Pb12 (s) Pb2+ + 21- Ksp = [Pb2+1 [I-r *The greater the ksp the more soluble the solid is in 1-120. ](./media/image172.png)

Question 1 (b)

(ii) Calculate the minimum concentration of F-(aq) necessary to initiate precipitation of the salt selected in part (b)(i). 3.5 = = 3.5 x 10-10 = \[F-\]2 -10 = 10-5M 3.5 x 10 1 point is earned for the correct value of \[F - \].

Question 3 (c)

(c) Calculate the magnitude of q, the thermal energy change, when the MgO was added to the 1.0 M HCl(aq). Include units with your answer. - mcAT q calorimeter In trial 2, OR In trial 3, OR In trial 4, q cal = q cal = q cal = (4.18 Jh 1.0 g) 100.0 mL x + 0.50 g mL ) ( 4.18 Jh 1.0 g) 100.0 mL x + 0.25 g mL ) ( 4.18 J h 1.0 g h ) (4.00 100.0 mL x + 0.50 g mL ) c c c ) = 1700 Jor 1.7kJ ) = 880 JorO.88kJ 1 point is earned for the correct mass of the solution. 1 point is earned for the correct calculation of q for any frial with a valid AT and ) = 1700 Jor 1.7kJ correct units.

Question 3 (e)

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Question 4 (a)

:ä-p-ä: Phosphate Ion

  • Write ionic equation if possible

Question 5 (a)

(a) Describe TWO reasons why the pressure changes as the temperature of the C2H4(g) increases. Your descriptions must be in terms of what occurs at the molecular level. Two reasons are: (1) As the temperature increases, the of the molecules increases and the molecules collide with the container walls. (2) As the temperature increases, the of the molecules increases and the molecules strike the walls of the container with 1 point is earned for each correct reason.

Question 5 (e)

Energy Diagram for a Two-Step Reaction • Reactants transition state intermediate • Intermediate -9 transition state product rate-detennining transition state Ea=l •CHA + AHO = -26 overall AHO -25 reaction coordinate

Question 6 (c)

CH2C12 is polar, whereas CC14 is not. Therefore, CH2C12 interacts with H20 via dipole-dipole forces, while CC14 only interacts with water via dipole/induced dipole forces or LDFs, which would be weaker. As a result, CH2C12 has a greater solubility.

Question 6 (e)

  • hydrogen bonding

    C:\\8E425445\\852EE352-60A8-43EB-A33B-8042A84EBC3A\_files\\image180.png

    Hydrogen bonds

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